The remote host is missing an update to netkit-telnet-ssl announced via advisory DSA 529-1.

https://secure1.securityspace.com/smysecure/catid.html?in=DSA%20529-1

b0f discovered a format string vulnerability in netkit-telnet-ssl which could potentially allow a remote attacker to cause the execution of arbitrary code with the privileges of the telnet daemon (the 'telnetd' user by default). For the current stable distribution (woody), this problem has been fixed in version 0.17.17+0.1-2woody1. For the unstable distribution (sid), this problem has been fixed in version 0.17.24+0.1-2. We recommend that you update your netkit-telnet-ssl package.